Engine starting mechanism



? Jan. 23, 1951 w. A. BEVIS ET AL ENGINE STARTI/ILIG MECHANISM FiledNov. 6, 1947 Patented Jan. 23, 1951 -U-N-l T E-D S TAEIES 2,5394% I A II ENGIN'ESTARTINGMECHANISM William Albert "Bevis, Midfllesex, and.:Ernest Harry Charles "Thorpe, :Surrey, England, as- :-'signors to 0.:A. V. Limited, .Acton, London,

. Eng'land 'ApplicationNovember 6, 1-947,--'SerialNo. 1841336 InGreatBritain oictdberzl, 1946 l1- Claim. (01. 175-375) for vehicle andother internal combustion en- ,ginesj,jjof ,the kind in 'which anelectric motor 'supplie'd'with curreritfrom a battery is connectiblewith a gear wheel on the engine by an electromagnetically actuatedslidable pinion, the object of the invention being to provide improvedmeansfor controlling such a mechanism.

Thejinvention comprises the combination of an electromagnetic startingswitch, a manually operable switch controlling the starting switch, anelectromagnetic switch controlling the starting and manually operableswitches, a time switch controlling the latter electromagnetic switch,and an electromagnetic switch dependent on current supplied to the motorfor controlling the time switch,"the arrangement being such that thelast named electromagnetic switch causes the time switch to becomeoperative only after the engine has been properly started.

The accompanying diagram illustrates one embodiment of the invention.

Referring to the diagram, the engine starting motor is indicated by a.This is supplied with current from a battery 22 under the control of astarting switch operable by an electromagnet d. The motor a, battery 17,and starting switch 0 are arranged in a main electric circuit A. Theelectromagnet d is arranged in a parallel circuit B which is connectedto the main circuit A and contains a push-button or otherwise manuallyoperable switch e, and a normally closed switch 1 operable by anelectromagnet g.

In series with the motor and battery there is arranged in the maincircuit A the winding h of a normally closed electromagnetic switch 2'.This switch is so designed that it is held open by the current normallyrequired to operate the motor for starting the engine, and is allowed tore-close under the action of a spring when that current falls below apredetermined value as a consequence of the engine having been properlystarted. The switch i controls the circuit of a time switch 7'. In theexample illustrated by the diagram the time switch 1' comprises a pairof normally closed contacts arranged in series with the switch 1' andthe part of the circuit containing the switch e as shown, so that theswitches a, 2' are connectible across the main circuit A by the switche. One of the contacts of the switch 9' is carried or actuated by abi-meta'l strip 70 adapted to separate the contacts after an appropriateinterval of heating (say one second) by the current flowing through it.The switch 7' is bridged by a branch circuit C containing theelectromagnet 1g above mentioned which serves to =.-openthe switch J andalso to hold .open the contacts a which are initially separated by thebi-metal strip 70. The amount of current supplied to the circuit of thetime switch is controlled by a resistance m.

The parts above described are interconnected in the manner shown by thediagram, and the mode of action of the system is as follows:

When the driver closes his switch e the associated switch 0 is closed bythe electromagnet 11. Current now flows from the battery to the motorcausing the motor to be engaged with the engine and rotated. The amountof this current is such that it causes the switch 2 to be opened,thereby preventing premature actuation of the time switch 7'. Should amomentary firing occur in the engine, the motor current may fall invalue sufficient to allow the said switch to close, but this is of noconsequence, as the time switch will not respond to a momentary drop inthe motor current, or a succession of such drops of short duration. Whenhowever, the engine has been properly started the motor current will notonly drop but will remain steady at its lower value,

. and the switch 2 which is actuated by this current will not only closebut remain closed. The time switch 7' then comes into action after anappropriate time interval, causing the switch f to be opened, therebyopening the circuit B containing the electromagnet d which in turnallows the switch 0 to open the circuit A. The supply of current to themotor is thereby interrupted. When the driver releases his switch e, thesystem resumes its initial condition.

By this invention we are able advantageously to simplify engine startingmechanisms of the kind specified. The invention is not, however,restricted to the example described, as subordinate details may bemodified to suit difierent requirements.

Having thus described our invention what we claim as new and desire tosecure by Letters Patent is:

A control system for a starting mechanism of the kind specified,comprising in combination a main electric circuit, a normally openelectromagnetic starting switch in said circuit, a parallel circuitconnected to said main electric circuit, electromagnetically operablemeans responsive to current in said parallel circuit for closing saidstarting switch, a normally open manually operable switch and a normallyclosed electromagnetic switch arranged in series with each other in saidparallel circuit, a normally closed time switch and a second normallyclosed electromagnetic switch arranged in series with each other andconnectible across said main circuit by said manually operable switch, abranch circuit bridging said time switch, electromagnetically operablemeans responsive to current in said branch circuit for opening the firstmentioned normally closed electromagnetic switch when said time switchopens, and for retaining said time switch in its open position, andelectromagnetically operable means responsive to current in said mainelectric circuit for opening said second normally closed electromagneticswitch when the flow of current in said main electric circuit exceeds apredetermined amount, and thereafter allowing reclosure of said secondnormally closed electromagnetic switch to permit current flow throughsaid time switch only when the current in said main circuit falls belowsaid amount.

WTLLIAM ALBERT BEVIS. ERNEST HARRY CHARLES THORPE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name, 7 Date 1,484,539 Williams et al. iFeb. 19, 1924 1,607,497 Williams et a1 Nov. 26, 1926 1,763,197 SpeiserJune 10, 1930 1,901,285 Christian Mar. 14, 1933 1,902,646 Krapp Mar. 21,1933 1,904,187 Whitney Apr. 18, 1933 1,942,591 Christian Jan. 9, 19342,009,036 Whitney July 23, 1935 2,020,749 Watson Nov. 12, 1935 2,079,129Morris May 4, 1937 2,165,133 Cuthbertson July 4, 1939 2,174,101 WilliamsSept. 26, 1939 2,213,160 Elkin Aug. 27, 1940 2,436,633 Curzon Feb. 24,1948 FOREIGN PATENTS Number Country Date 515,498 Great Britain Dec. 6,1939

